A facebook employee explained me how tracking works. Its not the email address Meta is concerned about. Its the IP, device identifiers and location. Meta doesnt care about the email at all apart from sending you emails for notification. Even with a fake email they exactly know who you are. Let’s say you visit CNN.com which has facebook tracker. Facebook has the IP and the device identifiers. Now you login with fake email account on Instagram, facebook knows that’s the IP ans the same device hence it “must” be the same person That’s how facebook creates shadow profiles.
Try going down the page and looking for the categories with more than a few bits of identifying information. I’m running LibreWolf with just uBlock Origin and Dark Reader (which I don’t think influences results) and I’m able to get nearly-unique, instead of unique (but I do get unique on default settings). TBB gets non-unique, which is a good set of results to compare to.
In my case I noticed that my fonts were really unique so I set
browser.display.use_document_fonts = 0. Also I use my WM to set my page resolution to 1920x1080, which seems to have a better fingerprint than the default LibreWolf floating resolution of 1600x900 (and even the letterboxing resolutions, from what I can tell).I just spent some time testing again and checking for anything else. RFP does force a generic user agent, but unfortunately it keeps the version information and I can’t figure out how to change it with RFP on. Would be nice to set it to the ESR version used by TBB (which has lower bits), but I’m not sure if that would lead to a more unique fingerprint (if, say, a feature was detected that is available in later versions but not ESR).
Edit: just tried Mullvad browser, and it’s non-unique! Might be the best option.